Oregon lawmakers are considering a bill to ban tiny plastic beads that show up in everything from toothpaste to facial scrubs and end up in waterways, harming fish that mistake them for food, environmentalists and lawmakers said on Thursday.

A handful of other states, including Washington and California, are also considering banning the tiny pieces of plastic known as microbeads. Illinois became the first state to ban them last year.

“It’s really about the environment, and they’re non-biodegradable,” said the Oregon bill’s chief sponsor, Democratic state Representative Carla Piluso. Lawmakers will hold a public hearing on the bill in Salem on Tuesday.

The microbeads, often used as a skin exfoliant, are so small they often slip through wastewater treatment systems and end up in nearby waterways, according to the National Oceanic and Atmospheric Association.

The Illinois ban came after a team of researchers with 5 Gyres Institute, a California-based environmental group, found high levels of beads in 2012 from samples taken at Lakes Erie, Superior and Huron. Scientists have also found beads in the ocean.

“Those toxins can transfer from the plastic and concentrate up the food chain,” said Anna Cummins, executive director of 5 Gyres. “By extension, the concern is both for the health of our marine ecosystem and our marine wildlife but also to humans that are at the top of the food chain and consume seafood.”

Oregon’s bill would ban the manufacture and sale of microbeads in personal care products. The Personal Care Products Council, a trade association representing the cosmetics and personal care products industry, supports the bill.

“The industry shares a common interest with other stakeholders in protecting the environment and the industry takes questions regarding the presence of microbeads in our waterways very seriously,” Karin Ross, director of government affairs for the council, said in a statement.

Some manufacturers have already pledged to phase microbeads out of their products. The Oregon legislation, if passed, would take effect in December 2019 to give companies time to comply.

Cummins complained the language leaves room for a loophole because it defines the plastic as non-biodegradable, potentially allowing the industry to use biodegradable plastic that breaks down only at high heat facilities.

Personal Care Products Council officials said it is not the industry’s intent to use biodegradable plastic available today, such as polylactic acid.